為改善(shan)混(hun)(hun)凝(ning)土(tu)(tu)(tu)(tu)拌(ban)合物的(de)和(he)易性(xing)(xing)(xing)或硬(ying)化后混(hun)(hun)凝(ning)土(tu)(tu)(tu)(tu)的(de)性(xing)(xing)(xing)能，節約水泥，在(zai)混(hun)(hun)凝(ning)土(tu)(tu)(tu)(tu)攪(jiao)拌(ban)時也可摻入磨細的(de)礦物材(cai)料──摻合料。它分為活性(xing)(xing)(xing)和(he)非活性(xing)(xing)(xing)兩類。摻合料的(de)性(xing)(xing)(xing)質和(he)數量，影響混(hun)(hun)凝(ning)土(tu)(tu)(tu)(tu)的(de)強度(du)、變形、水化熱、抗滲性(xing)(xing)(xing)和(he)顏色等(deng)。它是(shi)(shi)由(you)膠結材(cai)料，骨料和(he)水按一定(ding)(ding)比(bi)例配制(zhi)(zhi)，混(hun)(hun)凝(ning)土(tu)(tu)(tu)(tu)制(zhi)(zhi)品(pin)，經(jing)攪(jiao)拌(ban)振搗成型，在(zai)一定(ding)(ding)條件下養護而(er)成的(de)人造石材(cai)。混(hun)(hun)凝(ning)土(tu)(tu)(tu)(tu)具有原料豐(feng)富，價格低(di)廉，生產工(gong)藝簡(jian)單的(de)特點，因而(er)使(shi)其(qi)用(yong)量越來(lai)越大。混(hun)(hun)凝(ning)土(tu)(tu)(tu)(tu)是(shi)(shi)土(tu)(tu)(tu)(tu)木工(gong)程中(zhong)用(yong)途、用(yong)量大的(de)一種建(jian)筑材(cai)料。按預(yu)定(ding)(ding)性(xing)(xing)(xing)能設計和(he)制(zhi)(zhi)作混(hun)(hun)凝(ning)土(tu)(tu)(tu)(tu)，研制(zhi)(zhi)輕質，高強度(du)，多功能的(de)混(hun)(hun)凝(ning)土(tu)(tu)(tu)(tu)新(xin)品(pin)種。

混(hun)(hun)凝(ning)(ning)(ning)(ning)(ning)土(tu)(tu)裂(lie)縫分類(lei)及(ji)裂(lie)縫出現收(shou)集(ji)的(de)資(zi)料，根據地(di)下工程和(he)防水混(hun)(hun)凝(ning)(ning)(ning)(ning)(ning)土(tu)(tu)的(de)防水要求，對混(hun)(hun)凝(ning)(ning)(ning)(ning)(ning)土(tu)(tu)裂(lie)縫而(er)言，可分為(wei)有害(hai)(hai)裂(lie)縫和(he)無害(hai)(hai)裂(lie)縫。顏色，預制(zhi)混(hun)(hun)凝(ning)(ning)(ning)(ning)(ning)土(tu)(tu)制(zhi)品，好的(de)混(hun)(hun)凝(ning)(ning)(ning)(ning)(ning)土(tu)(tu)的(de)顏色與原混(hun)(hun)凝(ning)(ning)(ning)(ning)(ning)土(tu)(tu)相似度極高。普通的(de)與原混(hun)(hun)凝(ning)(ning)(ning)(ning)(ning)土(tu)(tu)基本(ben)相似，混(hun)(hun)凝(ning)(ning)(ning)(ning)(ning)土(tu)(tu)制(zhi)品定制(zhi)，而(er)劣質(zhi)的(de)則是發青(qing)發黑。普通混(hun)(hun)凝(ning)(ning)(ning)(ning)(ning)土(tu)(tu)即是我們在(zai)建筑中常(chang)用的(de)混(hun)(hun)凝(ning)(ning)(ning)(ning)(ning)土(tu)(tu)，表觀密度為(wei)1950～2500Kg/m3;，集(ji)料為(wei)砂、石(shi)。

這種混(hun)凝(ning)(ning)(ning)土(tu)(tu)(tu)的(de)水泥(ni)用(yong)量較普通混(hun)凝(ning)(ning)(ning)土(tu)(tu)(tu)低，新型混(hun)凝(ning)(ning)(ning)土(tu)(tu)(tu)制品，與水泥(ni)穩定碎(sui)(sui)石(shi)、二灰(hui)碎(sui)(sui)石(shi)等常用(yong)半剛性材(cai)料(liao)相比(bi)，具有(you)(you)較高(gao)(gao)的(de)強度(du)、剛度(du)和(he)整體(ti)性，抗沖刷、抗凍性能良好。特殊的(de)混(hun)凝(ning)(ning)(ning)土(tu)(tu)(tu)，比(bi)如發泡保溫混(hun)凝(ning)(ning)(ning)土(tu)(tu)(tu)可(ke)能只有(you)(you)幾百公斤(jin)每(mei)(mei)立方，陶粒(li)混(hun)凝(ning)(ning)(ning)土(tu)(tu)(tu)1800左右，防輻射的(de)重(zhong)混(hun)凝(ning)(ning)(ning)土(tu)(tu)(tu)可(ke)以(yi)達(da)到(dao)3500公斤(jin)每(mei)(mei)立方甚至更高(gao)(gao)。結構性能不(bu)(bu)同(tong)(tong)：所以(yi)配制不(bu)(bu)同(tong)(tong)的(de)素混(hun)凝(ning)(ning)(ning)土(tu)(tu)(tu)的(de)區別在于有(you)(you)沒有(you)(you)鋼筋，但不(bu)(bu)一定由水泥(ni)做為(wei)膠凝(ning)(ning)(ning)材(cai)料(liao)；而貧混(hun)凝(ning)(ning)(ning)土(tu)(tu)(tu)是指用(yong)較少(shao)量水泥(ni)做膠凝(ning)(ning)(ning)材(cai)料(liao)的(de)混(hun)凝(ning)(ning)(ning)土(tu)(tu)(tu)，一般每(mei)(mei)立方砼(tong)為(wei)100～200kg。